Induction of heme oxygenase-1 in LMH cells. Comparison of LMH cells to primary cultures of chick embryo liver cells

摘要

Heme oxygenase catalyzes the degradation of heme into biliverdin, carbon monoxide, and iron. Two forms of this enzyme, heme oxygenuse-l and -2, have been identified; only heme oxygenase-1 is subject to induction by heme, metal ions, and other chemical and physical perturbations (e.g. drugs, oxidants, and heat shock). Primary chick embryo liver cells are widely used for the study of heme metabolism because of (heir ease of preparation, low cost, and high degree of similarity to human heme metabolism. Nonetheless, this system has some limilalions: new cultures must be prepared every week; the resulting cell populations arc non-homogeneous; and cells are short-lived, limiting the feasible duration of time course and transfection studies. LMH cells are the first chicken hepatoma cell line to be established. The aim of this study was to chtiraeler the regulation of heme oxygenase-1 in LMH cells, and to compare this regulation to that previously described in primary chick embryo liver cells. The induction of heme oxygenase-1 was assessed by measuring changes in tnRNA levels or en yme activities in response to several treatments, including heme, heavy metals, sodium arsenile, and heal shock, which have been shown to increase the expression of heme oxygenase. Similarities were observed with respect to regulation of home oxygenase-1 expression in primary hepatocytes and LMH cells. We report the first measurable heat shock response of home oxygenase-1 in CELC or LMH cells; and show that LMH cells are a useful model for the study of heme oxygenase-1 regulation.